Can you recommend a good CAD program?

[ameerjaiswal]

Hi, I am a huge fan of the newer studless design, but I find it quite hard to build with it because it takes many iterations.
That's why I am currently searching for a good Lego CAD program to develop technic mocs. If found the Lego Digital Designer, LDraw and LeoCAD. I installed LDD and I think it works nice, but I'm missing some features. Since there are alternatives, I suspect that they have additional features which LDD has not.
I'm looking for the following features:[color=#333333]https://subwaysurfers.vip/ https://psiphon.vip/ https://hillclimbracing.vip/

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• replace parts
  
  
• modular building (import of pre-build assemblies)
  
  
• Import part lists from sets you own
  
  
• generating (and modifying) an instruction
  
  
• validation of gears and checking for degrees of freedom
  

I know there is propably no porgram which can handly all of this. That's why I want to ask people who are experienced with Lego CAD, which program they prefer and why.
Thank you in advance!